Short SC.1

https://en.wikipedia.org/wiki/Short_SC.1

The Short SC.1 was the first British fixed-wing vertical take-off and landing
(VTOL) jet aircraft. It was developed by Short Brothers. It was powered by an
arrangement of five Rolls-Royce RB108 turbojets, four of which were used for
vertical flight and one for conventional horizontal flight. The SC.1 had the
distinction of being the first British fixed-wing VTOL aircraft and the first
one to transition between vertical and horizontal flight modes; it was also the
first VTOL-capable aircraft with a fly-by-wire control system.

The SC.1 was designed and produced in response to a Ministry of Supply (MoS)
requirement for a suitable aircraft for conducting flight studies into VTOL
flight, as well as specifically into the transition between vertical and
horizontal flight. Two prototypes were used for flight testing between 1957 and
1971. Research data from the SC.1 test programme contributed to the development
of the Hawker Siddeley P.1127 and the subsequent Hawker Siddeley Harrier, the
first operational VTOL aircraft.

In October 2012, the Short SC.1 received Northern Ireland's first Engineering
Heritage Award as a recognition of its significant achievement in the
engineering field.

The SC.1 has its origins in a submission by Short Brothers to meet a Ministry of
Supply (MoS) request for tender (ER.143T) for a vertical take-off research
aircraft, which had been issued in September 1953. On 15 October 1954, the
proposed design was accepted by the Ministry and a contract was promptly placed
for two aircraft to meet Specification ER.143D. As envisioned, the aircraft was
to be used for a series of flight tests to investigate its behaviour during the
transition between vertical and horizontal flight modes, to determine the
optimum and minimum level of assistance required from the auto-stabiliser during
the transition process, to uncover likely operational issues, and to develop
related support aids and equipment for the pilot to develop an all-weather
approach and landing system.

Short constructed two prototypes, designated XG900 and XG905.

The Short SC.1 was a single-seat low wing tailless delta wing aircraft of
approximately 8,000 lb all-up weight (max. 7,700 lb for vertical flight). It was
powered by four vertically-mounted, lightweight Rolls-Royce RB108 lift engines
that provided a total vertical thrust of 8,600 lb, along with a single RB.108
cruise engine in the rear of the aircraft to provide thrust for forward flight.
The lift engines were mounted vertically in side-by-side pairs in a central bay
so that their resultant thrust line passed close to the centre of gravity of the
aircraft. These pairs of engines could be swivelled fore-and-aft to produce
vectored thrust for acceleration/deceleration along the aircraft's longitudinal
axis.

During conventional flight, the lift engines would be shut down; before
beginning the transition from horizontal to vertical flight, they would be
started using compressed air from the single cruise engine. The compressed air
provided the initial rotation of the engine but a pressure drop from intake to
exhaust had to be present also as the compressed air alone was not adequate for
reaching idle speed. Considerable wind-tunnel and flight development of the air
intake was required because at the start of transition from horizontal flight
vertically-mounted engines have to tolerate a crosswind equal to the forward
flight speed without surging or excessive vibrations. The required uniformity of
flow was achieved with the help of a set of 7 hinged gills which opened to a
forward-facing position to direct air into a plenum which supplied the engines.
The behaviour of a vertically-mounted RB108 in terms of re-ingestion and ground
erosion had been investigated with an installation representative of that
intended for the SC.1 during ground operation in a Meteor at Hucknall Aerodrome.
Initially, a series of scuttles were fitted to the exit nozzles of the lift
engines to maintain a low-pressure environment beneath the engines to ensure
that the engine rotor would be "windmilling" in the correct direction prior to
supplying the compressed air for starting; due to the effectiveness of intake
and engine design changes, the scuttles became unnecessary.

The cockpit layout was mainly conventional, but complicated by the large number
of systems the pilot had to monitor. For its role as a research aircraft it had
comprehensive recording equipment.


Role
Experimental aircraft

Manufacturer
Short Brothers

Designer
Hugh Graham Convay
(Shorts chief engineer)

First flight
2 April 1957 (CTOL)
26 May 1958 (VTOL)

Retired
1971

Status
Retired and preserved

Primary user
Royal Aircraft Establishment

Number built
2


Constructed at Short's Belfast factory in Northern Ireland, the first SC.1
prototype, XG900, first undertook initial engine runs at this facility. After
being transported by sea to England, XG900, which was initially fitted only with
the propulsion engine, was delivered to the Royal Aircraft Establishment (RAE)
at Boscombe Down to begin the flight test programme. On 2 April 1957, the
prototype conducted the type's maiden flight, which was also its first
conventional takeoff and landing (CTOL) flight.

As a result of ground suitability tests, it was determined that conventional
runway concrete, pavement, and even grass strips would be adequate for vertical
takeoff and landing of the SC.1; however, debris that may be forced out from
imperfect surfaces would pose a risk to personnel but not to the aircraft
itself. The test programme also allowed experience upon the maintenance and
serviceability of a VTOL aircraft to be acquired, even though these were not
primary objectives of the design nor the research effort; throughout the
programme, an overall average of 2.6 flights were performed per week. While
numerous errors with the auto-stabiliser were reported during flights, no fault
ever occurred that endangered the aircraft or had any effect upon its control.

Testing found significant difficulty in measuring actual engine thrust, leading
to further tests using improved intakes and instrumentation. Ultimately, the
engines proved to be far less problematic than might have been expected
considering the experimental nature of the aircraft and its power-plants; and
when faults occurred in the triplex auto-stabiliser they were easy to locate, in
part due to the system's self-checking nature. According to a Ministry of
Aviation report, the SC.1 was determined to have been an effective research
vehicle when operated within the limits imposed by its small size and restricted
capacity; however it was found that a larger aircraft would be necessary for
more extensive tests of the instruments and guidance equipment.

The SC.1 flew for over ten years, during which it provided a great deal of data
that served to influence later design concepts such as the "puffer jet" controls
on the Hawker Siddeley P.1127, the precursor of the Hawker Siddeley Harrier. The
flight testing work relating to vertical takeoff and landing techniques and
technologies also proved to be invaluable, and helped further Britain's lead in
the field. The Short SC.1 was ultimately rendered obsolete by the emerging
Harrier which, amongst other things, proved that it was unnecessary to carry an
additional four engines solely for the purposes of lift-off and landing.

Specifications

General characteristics
Crew: 1
Length: 25 ft 6 in (7.77 m)
Wingspan: 23 ft 6 in (7.16 m)
Height: 10 ft 8 in (3.25 m)
Wing area: 211.5 sq ft (19.65 m2)
Aspect ratio: 2.61:1
Airfoil: NACA 0010
Empty weight: 6,260 lb (2,839 kg)
Gross weight: 7,700 lb (3,493 kg) (VTOL operations)
Max takeoff weight: 8,050 lb (3,651 kg) (CTOL operations)
Powerplant: 1 × Rolls-Royce RB108 turbojet, 2,130 lbf (9.5 kN) thrust (forward
flight)
Powerplant: 4 × Rolls-Royce RB108 turbojets, 2,130 lbf (9.5 kN) thrust each

Performance
Maximum speed: 246 mph (396 km/h, 214 kn)
Range: 150 mi (240 km, 130 nmi)
Service ceiling: 8,000 ft (2,400 m)
Rate of climb: 700 ft/min (3.6 m/s)
Wing loading: 38.1 lb/sq ft (186 kg/m2)
Thrust/weight:
(CTOL): 0.265
(VTOL): 1.11




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